A new study shows that visual outcome measured at 3 or fewer days after cataracts surgery is a good indicator of long-term outcome and can be used as a measure of surgical quality in regions of the world in which longer-term follow-up is rare.
Cataracts are the most common cause of blindness throughout the world, explain Nathan Congdon, MD, and colleagues in a study published in the July issue of the Lancet Global Health, Surgery is a highly effective remedy, with 90% of patients achieving best corrected vision of 6/12 or better with a good surgeon.
Clinics in developing nations often lack the adequate follow-up information needed to assess their surgeons' skills, however. In some countries, follow-up in the weeks to months after surgery may be as low as 20% to 30%.
"In the developed world, we expect patients to be able to return 4 to 5 times for follow-up visits," Dr. Congdon told Medscape Medical News. "That's very difficult for people in the developing world, who may have to struggle with bad roads, lack of transportation, or lack of money, among other issues."
Dr. Congdon, from the Division of Preventive Ophthalmology and State Key Laboratory, Zhongshan Ophthalmic Centre, Sun Yat-sen University, Guangzhou, China, and coauthors designed the Prospective Review of Early Cataract Outcomes and Grading (PRECOG) study "to test new approaches for the measurement of cataract surgical quality in settings with poor rates of follow-up," they write.
Forty hospitals in 11 countries across Asia, Africa, and Latin America each provided data on 40 to 120 consecutive patients scheduled for cataract surgery. Presurgical evaluations included an ocular examination with slit lamp and dilation of the pupil, as well as measurement of best visual acuity. Early postoperative examinations were performed within 72 hours of surgery, coinciding with hospital discharge at most centers. Patients who returned unprompted 40 days or more after surgery underwent a final follow-up examination. For patients who did not return after 40 days, hospital staff members employed incentives such as telephone calls and transportation subsidies to encourage them to come in, and after 3 months, clinicians started paying home visits to patients who still had not returned. Ultimately, all of the centers achieved follow-up rates greater than 90% except for Indonesia where the follow-up rate was 86%.
The participating hospitals recruited a total of 3708 patients with a mean age of 68 years. Small-incision cataract surgery was performed in 2297 patients (63%), phacoemulsification in 782 patients (21%), and extracapsular or intracapsular cataract extraction in 593 patients (16%). Data on type of surgery were missing for 36 patients. Early postoperative examinations were performed on 3062 of 3601 patients (85%) for whom a date was recorded. Of the original 3708 patients, 3441 (93%) underwent final examinations 40 or more days postoperatively.
Visual outcome between the early and late postoperative examinations was highly correlated both for all patients (Spearman's r s, 0.74; P < .0001) and for only those patients who returned unprompted (r s, 0.86; P < .0001). Hospitals in which fewer than 50%, or even fewer than 30%, of patients returned unprompted showed a correlation in postoperative visual outcome between those patients and everyone who had a final examination (r s, 0.71 [P = .002] and r s, 0.63 [P = .05], respectively).
"We started with the hypothesis that people who returned unprompted were not representative of all patients," Dr. Congdon told Medscape Medical News. "These data suggest that those who return are representative, and it held up even in hospitals in which fewer than 50% or 30% returned. That was a big surprise to [us]."
"This large study...is a welcome addition to the published work on this topic," Yuzhen Jiang, MD, PhD and Paul J. Foster, PhD, from the UCL Institute of Ophthalmology, University College London, United Kingdom, write in an accompanying comment. "These findings are especially important for planners and designers of blindness-prevention programs."
They describe particularly low follow-up rates in China, India, and Indonesia as "especially worrying," and laud Dr. Congdon and colleagues for demonstrating the effectiveness of strategies such as telephone calls and transportation subsidies at inducing more patients to return.
"This is an excellent study. It is especially important in the setting of international blindness and cataract surgery efforts, where a lot of patients may get lost to follow-up," said Natalie Afshari, MD, professor of ophthalmology and chief of cornea and refractive surgery, Shiley Eye Center, University of California, San Diego, School of Medicine. Dr. Afshari, who was not involved in this research, was particularly impressed by its scope: "They had 40 centers in 11 countries on several continents. Very nice work."
In nations in which resources are limited and follow-up may be a problem, "it's nice to feel confident that what the patient sees at around 3 days is well-correlated with later outcomes, based on this study," Dr. Afshari added.
"These findings show we can accurately measure quality with data we can easily collect even in places that can't measure for glasses and are doing older styles of cataract surgery," said Dr. Congdon, who is also affiliated with ORBIS International, a nongovernmental organization dedicated to saving sight worldwide. "That's an encouraging and important message."
Support was provided by the Fred Hollows Foundation, ORBIS International, Helen Keller International, the International Agency for the Prevention of Blindness/VISION 2020 Latin American Regional Office, and the Aravind Eye Care System. Dr. Congdon is supported by a Thousand Man Plan program grant from the Chinese government. The authors, editorialists, and Dr. Afshari have disclosed no relevant financial relationships.
Lancet Glob Health. 2013;1:e37-e45, e9-e10. Article full text, Comment full text
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Cite this: Cataract Surgery Globally May Only Need Short-term Follow-up - Medscape - Jun 29, 2013.